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Making Comparisons


Making Comparisons is a way of thinking about two or more objects, ideas and/or events to find out how they are the same and how they are different. Knowing this information allows students to sort, classify and organize objects, ideas and/or events, to connect prior knowledge about them to new knowledge, and to develop appropriate comparative vocabulary.

Why use it?

  • To help students develop an understanding of the relationships between objects, ideas and/or events.
  • To activate prior knowledge of objects, ideas and/or events.
  • To use the skill of Comparing & Contrasting to explain what is the same and what is different between and among different objects, ideas and/or and events.
  • To use the skill of Sorting & Classifying to make further connections between and among objects, ideas and/or events.
  • To develop appropriate comparative vocabulary (e.g., that indicates a comparison or contrast, such as alike, similar, different).

Tips for success

  • Encourage students to observe attributes of ideas, objects and/or events and identify those important for their purpose.
  • Recognize that initially the criterion/criteria students choose to sort/classify/organize materials, objects and/or events may not what we as adults might consider a recognized class. Allow students to explain their thinking and then challenge them by providing your criterion/criteria for comparing/contrasting and classifying/organizing characteristics of materials, objects and/or events

How do I use it?

  • Provoke situations where a comparison is required (e.g., put two or more versions of the same fairy tale in the class library, display life cycles of a variety of familiar animals, have a collection of similar tools for a task in a Design & Build challenge).
  • Introduce the terms criterion/criteria to the students and explain that criteria are used to help us to compare/contrast the characteristics of objects, ideas and/or events to determine what is the same/different.
Example of students comparing footwear to see which is more appropriate for winter. Source: Let’s Talk Science
Image of Interactive White Board Venn Diagram template Source: Let’s Talk Science
  • Model the use of a graphic organizer like a grid chart to show students how they can sort/classify/organize the characteristics of materials, objects and/or events (see Making Comparisons examples).
  • Choose two or more familiar items related to an area of student interest (e.g., objects or materials related to having a litter-free lunch).
  • Ask students observe the similarities and differences among the items and record their observations using a graphic organizer.
  • Ask students to identify how they made their choices in identifying where to place the items on the graphic organizer.
  • Reinforce that the word criterion/criteria is the word used for these choices.
  • Ask students to justify their choices of criteria.
  • Discuss how criterion/criteria can help us to understand the relationship between and among two or more ideas, objects and/or events.


  • Ask one student/group of students to determine criterion/criteria for some idea, objects and/or events and then have another student/group of students use these student-generated criteria to Compare & Contrast and sort & classify the items.

Related Skills